This chapter aims to introduce Karl Ludwig Michelet and his work, with particular focus on his theory of psychology, which has never been systematically analyzed. I will argue that Michelet’s book on Anthropologie und Psychologie oder die Philosophie des subjectiven Geistes is grounded in Georg Wilhelm Friedrich Hegel’s Philosophy of subjective spirit, but at the same time goes beyond it. The chapter takes into particular consideration Michelet’s understanding and classification of mental derangement, which was in itself a highly debated theme in the fields of philosophy, law, and psychology in nineteenth century Germany. From this analysis, we get the picture of a philosopher who aims to give Hegelian scientific and philosophical methods and insights a broader application by further developing Hegel’s thought, correcting it where needed, and taking into account the debates of his time. In addition, we get the picture of a thinker whose psychological thought anticipates, on Hegelian bases, some issues later developed and established within psychoanalysis and depth psychology and who defends a quite original view of mentally deranged people for that time: that is, that they count as still rational human beings and can be healed. This is an idea that can be traced back to the French psychiatrist Philippe Pinel and to his own fundamental experiences as internist, which had great resonance in Germany at the time.